Post-earthquake relaxation using a spectral element method: 2.5-D case
The computation of quasi-static deformation for axisymmetric viscoelastic structures on a gravitating spherical earth is addressed using the spectral element method (SEM). A 2-D spectral element domain is defined with respect to spherical coordinates of radius and angular distance from a pole of symmetry, and 3-D viscoelastic structure is assumed to be azimuthally symmetric with respect to this pole. A point dislocation source that is periodic in azimuth is implemented with a truncated sequence of azimuthal order numbers. Viscoelasticity is limited to linear rheologies and is implemented with the correspondence principle in the Laplace transform domain. This leads to a series of decoupled 2-D problems which are solved with the SEM. Inverse Laplace transform of the independent 2-D solutions leads to the time-domain solution of the 3-D equations of quasi-static equilibrium imposed on a 2-D structure. The numerical procedure is verified through comparison with analytic solutions for finite faults embedded in a laterally homogeneous viscoelastic structure. This methodology is applicable to situations where the predominant structure varies in one horizontal direction, such as a structural contrast across (or parallel to) a long strike-slip fault.
Citation Information
Publication Year | 2014 |
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Title | Post-earthquake relaxation using a spectral element method: 2.5-D case |
DOI | 10.1093/gji/ggu114 |
Authors | Fred Pollitz |
Publication Type | Article |
Publication Subtype | Journal Article |
Series Title | Geophysical Journal International |
Index ID | 70175908 |
Record Source | USGS Publications Warehouse |
USGS Organization | Earthquake Science Center |